Developed for the Office of Naval Research in 2009, this vehicle was designed to conduct ocean underwater surveillance, enabling it potentially to detect chemical spills, monitor the presence of ships and submarines, and observe the migration of schools of fish.
Recently, a team at VirginiaTech has improved the performance of this silicone swimmer, enabling it to better overcome the limitations of its artificial skin and better mimic the true motion of a jellyfish. Details on this new design and how it might provide new insights into jellyfish propulsion mechanisms will be presented at the 2011 meeting of the American Physical Society’s Division of Fluid Dynamics in Baltimore, Md., Nov. 20-22.
According to VirginiaTech mechanical engineer Alex Villanueva, Robojelly looks very similar to an actual jellyfish. “Its geometry is copied almost exactly from a moon jellyfish [Aurelia aurita],” he said. The robot is built out of silicone and uses shape memory alloy (SMA) actuators to swim.
To move through the water, the natural animal uses the bell section of its body, which deforms and contracts to provide thrust. The lower, or lagging, section of the bell is known as the flexible margin, and it deforms slightly later in the swimming process than the rest of the bell. Until recently, however, Robojelly lacked this crucial piece of anatomy in its design.
Villanueva and his colleagues tested a number of different designs for their robot, some with and without an analog to a flexible margin. Initially, the artificial materials used in construction presented a problem. Unlike their natural counterparts, the artificial materials tended to fold as they deformed, reducing Robojelly’s performance. After testing a number of designs and lengths for the folding margin, the engineers discovered that cutting slots into the bell reduced this unwanted folding effect.
This gave Robojelly a truer swimming stroke, as well as a big boost in speed.
“These results clearly demonstrate that the flap plays an important role in the propulsion mechanism of Robojelly and provides an anatomical understanding of natural jellyfish,” said Villanuerva.
The talk, “Effects of a flexible margin on Robojelly vortex structures,” is at 3:05 p.m. on Tuesday, Nov. 22, 2011, in Room 324. Abstract: http://absimage.aps.org/image/MWS_DFD11-2011-001706.pdfMORE MEETING INFORMATION
Charles Blue | Newswise Science News
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Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
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Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
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An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
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